Mid-afternoon in the greasy spoon at the dilapidated Velky Strahovsky stadium and Petr Cech is reflecting on another frenetic summer off. International commitments were followed by an all too brief sojourn in Spain that, he ruefully admits, will leave him as Chelsea's pastiest player on his return next week. The past few days have been spent attempting to inspire the next generation at the hugely popular junior football academy he runs annually for children back home. And then there's the gig.

"Oh yes, I have the festival on Friday," he says, the apparent afterthought an appearance at the Czech Republic's equivalent of Glastonbury, Rock for People, where 12,000 will squeeze into a tent at one of the event's six stages to listen to the goalkeeper drum with the indie-rock band, Eddie Stoilow. Muse and Arctic Monkeys have topped the bill in recent years, while acts over the preceding four days vary from Queens of the Stone Age to Foals, Bloc Party to Thirty Seconds to Mars. Cech has crammed two rehearsals into his hectic schedule. "It'll be nerve-racking," he says. "If the drummer goes wrong in a band, the whole thing falls apart."

Apprehensive he may be but if that experience moves the 31-year-old from his comfort zone, normality will soon kick in. Chelsea have a familiar face back in charge and waiting to welcome the squad for pre-season on Monday and everyone, whether seasoned professional or bright young thing, has something to prove. José Mourinho has already indicated reputations will count for nothing. He will have everything painstakingly mapped out for the gruelling first week ahead.

There is a new project to oversee, a new side to inspire and Cech, for one, is more than happy to beat the drum for the manager's second coming.

Yet he has also been here before. This will be the sixth time Cech has arrived at Cobham after the close-season break to find a newly appointed manager in place, if Roberto Di Matteo's rather downbeat summer coronation a year ago is included. Mourinho was his first manager at Chelsea and is the latest to arrive preaching stability and longevity. "Every manager who comes in has ideas, a long contract, and you hope he stays forever. Every year I sit here saying: 'This is a great manager with a lot of experience, one of the top managers in the world, and we hope he stays for years and years.' Then the 'other thing' happens as well and, two years later, I'm back here saying the same thing [about someone else]. That is how football goes.

"It all depends on circumstances, on the way the team progresses, but with José I only have great memories. He gave me the chance to be the No1 at Chelsea. I was 22, joining a big club [from Rennes] where Carlo Cudicini was first-choice, a player who had the most clean sheets the previous season. You think: 'Well, if the new manager comes in and just picks him then I'm dead.' That was the challenge. But he gave me the opportunity to start and show what I could do, and that is when my career kicked on. Secondly, obviously, we had such a successful time. I hope that we can reproduce that now and even push it forward."

Even emulating that glittering first spell, which yielded two Premier League titles, an FA Cup and two League Cups in a little over three years, would constitute a triumph though, for Chelsea, the Portuguese's return means so much more. Mourinho will rouse those in the stands as much as he galvanises on the pitch. "He will always make you see what he wants you to see," Cech says. "He knows his team, is careful how he manages his players, and everyone feels part of it. The work he puts in, all the small details in terms of preparation for the individual players … he is so demanding, but everyone is on top of his game whether he is playing or not. It makes people want to work.

"It's the mentality, the wording and the detail he puts into everything. He's a manager who'd rather lose than draw a game. Some would say: 'OK, if you can't win it, just don't lose it.' But with him that's not the case. He's all about winning, and winning the right way. 'Right' doesn't necessarily mean in a 'great' way, as in a nice way to watch. Sometimes you have to win a game 'ugly'.

"If you play against a team who are really physical you have to find the way to compete. In the Premier League, teams play different styles and it's almost impossible to play 'nice' football. But the 'right way' means you are tactically prepared and use the weapons to kill your opponent. Sometimes you impose the way you can play and you play football that is beautiful to watch; sometimes it's really scrappy, but you still need to win the game to win the title. This is the right way."

Mourinho departed abruptly in the autumn of 2007 – "It was a huge surprise because you never expect to break something that was working," Cech says – but returns to find the landscape changed. Sir Alex Ferguson has left Old Trafford; Manchester City, now under Manuel Pellegrini, continue to spend lavishly; Tottenham Hotspur are a menacing presence, while Arsenal and Liverpool hint at lofty ambition. Only Arsène Wenger and Mourinho of the managers who start the campaign have won the title. "We have an opportunity but City and United will still be the main threat," Cech says. "The Arsenal manager is under pressure as everyone keeps reminding him all the time since he won a trophy. They will want to show that they mean what they say, that they do want to challenge.

"But our ambition is the same: to try and win everything. The attraction – for the fans, the media, even the neutrals – is having Mourinho back and we'll all be under the spotlight, but it will not change the ambition of the club. He will judge better how we are different now to when he left. It's easier for someone who disappears and then comes back to see the changes, but I still believe he will find a great team with quality players, and facilities on a top level. Hopefully it will be something for him to start with."

Cech has spent his week offering youngsters the chance to take their own first steps towards a career in the game, with 130 children between seven and 15 and from all over the world – from South Korea to California, England to South Africa – put through their paces at Sparta Prague's academy complex. This is Cech's eighth year overseeing the summer school. "It's not only about football but to tell them about healthy food, the way they should look after the body and generally have respect for each other, learning how to work in teams," he adds. "We are not naive to think one week here will make them better people or better players but we try to teach them skills so that they don't need us for the rest of the year.

"A lot of them come back in winter or summer and you can see the progression. This is what gives us pleasure. Kids show pure emotions: when they are happy they are happy, when they are sad they are sad, but they come back with a smile on their faces, so we keep going every year." At around 6.15pm on Rock for People's YouTube stage in Hradec Kralove on Friday, it will presumably be Cech beaming from ear to ear. After that, work awaits.